The present invention relates to a storage system comprising a backup function.
Techniques pertaining to backup include, for example, a technique for performing data copy in a storage system (hereinafter, storage system data copy technique). This type of technique is disclosed in, for example, Japanese Unexamined Patent Application No. 2001-216185. This type of technique normally involves data of first logical volumes formed according to a plurality of storage devices that the storage system comprises being copied into second logical volumes formed according to these plurality of storage devices.
In storage system data copy techniques the capacity of the second logical volume is normally required to be the same as the capacity of the first logical volume serving as the copy original. For this reason, backup of the backed up data of a first logical volume across multiple generations requires the plurality of storage devices of the storage system to have an empty capacity of (first logical volume capacity×number of generations). The number of storage devices is restricted and, therefore, this presents a problem of how to backup first logical volume data across multiple generations. Not withstanding that each of the plurality of storage devices mounted in a storage system is normally interchangeable, this cannot be taken as meaning that the number of storage devices is limitless.